Non-destructive thermal conductivity detectoin of solder voids

ABSTRACT

Systems and methods can produce thermal images of the mounting of a thermally-enhanced integrated circuit (IC) upon a circuit board. The system includes a thermal imaging camera that is operable to image the thermal dissipation and/or conduction through the heat sink into a mounting pad on the substrate. In testing the thermally-enhanced IC, the substrate or IC is connected to a power source, and the IC is operated such that the IC begins to generate heat. As the heat is conducted or dissipated through the heat sink into the mounting pad, a thermal imaging camera can detect the heat conduction and/or dissipation through the heat sink into the substrate. If there are voids or other types of failures in the mounting of the IC, the thermal imaging camera can detect cooler or colder spots in the image.

BACKGROUND

Some new integrated circuits chips have better thermal dissipationfeatures. Once such integrated circuit (IC) package that has betterthermal dissipation features is the thermally-enhanced quad flack pack(QFP). The thermally-enhanced QFP includes a heat sink or pad mounted tothe bottom of the IC package that holds the IC. The heat sink is mountedto provide a thermal conduction path from the IC die to the substrateupon which the IC package is mounted. An example of a thermally-enhancedQFP is shown in U.S. Pat. No. 5,905,299 to Lucap or sold by AnalogDevices, Inc. of Norwood, Mass. for example, part no. SP-240-1. In orderto provide good thermal conductivity, the heat sink on the IC packageneeds to be mounted properly to a mounting pad on the substrate.

To ensure mounting wherein the thermal conductivity path is correct,solder must be applied over the entire surface of the heat sink and themounting pad without voids. However, this mounting can prove difficultand sometimes, errors occur in the mounting of the thermally-enhancedQFP. Thus, a testing regiment must be employed to determine if the ICspackage is mounted on the substrate properly. There are several methodsof possibly doing this. One may be visual inspection. However, this mayrequire the thermally-enhanced QFP to be removed to see how thesoldering process worked. As such, visual inspection cannot be a 100%test, but rather, the product must be sampled because the part wouldhave to be remounted or the part may be destroyed. In other instances,an X-ray machine may be used. However, X-ray inspection is moredifficult because both the mounting pad and the heat sink are underneaththe IC package of the IC and, as such, the X-ray has a difficult timeimaging the surface upon which the heat sink is mounted. Thus, currentlythere is no good way of testing the mounting of a thermally-enhanced QFPthat would test 100% of the parts and ensure good testing results.

SUMMARY

It is with respect to the above issues and other problems that theembodiments presented herein were contemplated. Systems and methods areprovided herein for imaging the mounting of a thermally-enhanced QFPupon a substrate. The system includes a thermal imaging camera that isoperable to image the thermal dissipation through the heat sink into themounting pad of the substrate. In testing the thermally-enhanced QFP,the substrate or IC is connected to a power source and the IC isoperated such that the IC begins to generate heat. As the heat isdissipated through the heat sink into the mounting pad, a thermalimaging camera can detect the heat conduction through the heat sink intothe substrate. If there are voids or other types of failures in themounting of the IC, the thermal imaging camera can detect cooler orcolder spots in the image. In properly mounted ICs, the thermal imagewill show heat dissipation substantially through the entire heat sinkand mounting pad. The testing process can scan each mounted chip as itcomes through a manufacturing line by powering on the IC and imaging thechip. Further, the thermal imaging is better suited for detectingmounting errors because the thermal image can scan heat dissipation evenwith the heat sink being underneath the packing of the IC.

Non-destructive methods of testing use x-ray equipment, which candetermine the density of solder as the beam penetrates the IC, heatspreader, solder, and copper pads of the circuit board. The x-ray candetermine whether the solder has filled the area beneath the IC, but thex-ray cannot inspect the system to ensure good wetting has occurred.Thus, the use of the x-ray equipment is limited to whether enough solderwas placed on the circuit board prior to placement of the IC. It cannotdetermine if the solder wetted to both the IC and mounting pad.

The embodiments use a thermal imaging camera to obtain an image of theback side of the circuit board as the assembly is operated. There is agreat difference in thermal conductivity between an air gap beneath theIC and a well soldered and wetted gap. There is also a difference in thethermal flow if the solder is not wetted to the IC. The circuit board isplaced in a thermally controlled environment (temperature and airflow iscontrolled). The thermal imaging camera images the circuit board beneaththe IC in question at discrete time intervals after power is applieduntil a steady state condition is observed.

The combination of initial thermal change and the steady state conditionwill differentiate between the several different common failures; 1)total lack of solder beneath the IC (voids), 2) lack of good wettingbetween the solder and the IC heat spreader (cohesive bonding), and 3)partial lack of solder bridging the gap.

The phrases “at least one”, “one or more”, and “and/or” are open-endedexpressions that are both conjunctive and disjunctive in operation. Forexample, each of the expressions “at least one of A, B and C”, “at leastone of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B,or C” and “A, B, and/or C” means A alone, B alone, C alone, A and Btogether, A and C together, B and C together, or A, B and C together.

The term “a” or “an” entity refers to one or more of that entity. Assuch, the terms “a” (or “an”), “one or more” and “at least one” can beused interchangeably herein. It is also to be noted that the terms“comprising”, “including”, and “having” can be used interchangeably.

The term “automatic” and variations thereof, as used herein, refers toany process or operation done without material human input when theprocess or operation is performed. However, a process or operation canbe automatic, even though performance of the process or operation usesmaterial or immaterial human input, if the input is received beforeperformance of the process or operation. Human input is deemed to bematerial if such input influences how the process or operation will beperformed. Human input that consents to the performance of the processor operation is not deemed to be “material”.

The term “computer-readable medium” as used herein refers to anytangible storage that participates in providing instructions to aprocessor for execution. Such a medium may take many forms, includingbut not limited to, non-volatile media, volatile media, and transmissionmedia. Non-volatile media includes, for example, NVRAM, or magnetic oroptical disks. Volatile media includes dynamic memory, such as mainmemory. Common forms of computer-readable media include, for example, afloppy disk, a flexible disk, hard disk, magnetic tape, or any othermagnetic medium, magneto-optical medium, a CD-ROM, any other opticalmedium, punch cards, paper tape, any other physical medium with patternsof holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, a solid state mediumlike a memory card, any other memory chip or cartridge, or any othermedium from which a computer can read. When the computer-readable mediais configured as a database, it is to be understood that the databasemay be any type of database, such as relational, hierarchical,object-oriented, and/or the like. Accordingly, the embodiments areconsidered to include a tangible storage medium and prior art-recognizedequivalents and successor media, in which the software implementationsare stored.

The terms “determine”, “calculate” and “compute,” and variationsthereof, as used herein, are used interchangeably and include any typeof methodology, process, mathematical operation, or technique.

The term “module” as used herein refers to any known or later developedhardware, software, firmware, artificial intelligence, fuzzy logic, orcombination of hardware and software that is capable of performing thefunctionality associated with that element.

The term “heat sink” as used herein refers to any device made from anymaterial that absorbs or dissipates heat produced by an electricalcomponent, such as an IC, to prevent overheating. Embodiments of heatsinks provide a heat conduction path for a device or may radiate heat.

The term “integrated circuit” or “IC” as used herein refers to anydevice comprising a number of connected circuit elements, such astransistors and resistors, fabricated on a chip of silicon crystal orother semiconductor material. Embodiments of the IC may also include apackage that encloses the chip.

The term “mount” or “mounting pad” as used herein refers to anymechanical device with which a component is attached to a circuit boardor chassis. Embodiments of the mounting pad can also function as a heatsink to conduct and dissipate heat.

The term “substrate” as used herein refers to a any device, such as aplate, a wafer, a panel, or a disk, of suitable material on (or in)which the components of a unit, such as an IC or printed circuit, aredeposited or formed. A circuit board may be one embodiment of asubstrate. Embodiments of the substrate may be able to conduct and/ordissipate heat.

The term “circuit board” as used herein refers to any flat piece ofmaterial, such as epoxy or phenolic resin, on which electricalcomponents are mounted and interconnected to form a circuit.

The term “die” as used herein refers to any wafer, of any size, ofuseful electrical material, such as a semiconductor or a precisionresistor chip. Embodiments of a die may include or form an IC that isenclosed in a package.

The term “package” as used herein refers to any enclosure for a die orIC. Examples of packages can include quad flat packs, ball grid arrays,pin grid arrays, dual inline packages, etc.

While exemplary embodiments are described, it should be appreciated thatindividual aspects can be separately claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is described in conjunction with the appendedfigures:

FIG. 1 is a block diagram of an embodiment of a test system andmanufacturing line;

FIG. 2A is a diagram of an embodiment of a circuit board onto which a ICmay be mounted;

FIG. 2B is a block diagram of an embodiment of an IC;

FIG. 2C is a block diagram of an embodiment of an integrated circuitboard where an IC is mounted on a circuit board;

FIG. 2D is another block diagram of an embodiment of an integratedcircuit board where an IC is mounted on a circuit board;

FIGS. 3A through 3C are diagrams of embodiments of thermal imagesproduced from a thermal imaging camera that viewed one or more of anmounted ICs;

FIG. 4 is a block diagram of an embodiment of a test system;

FIG. 5 is a flow diagram of an embodiment of a process for testing amounted thermally-enhanced IC;

FIG. 6 is a flow diagram of an embodiment of a process for testing amounted thermally-enhanced IC;

FIG. 7 is a block diagram of an embodiment of a computer systemenvironment in which the systems and methods may be executed; and

FIG. 8 is a block diagram of a computer system in which the systems andmethods may be executed.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a letter thatdistinguishes among the similar components. If only the first referencelabel is used in the specification, the description is applicable to anyone of the similar components having the same first reference labelirrespective of the second reference label.

DETAILED DESCRIPTION

The ensuing description provides embodiments only and is not intended tolimit the scope, applicability, or configuration of the claims. Rather,the ensuing description will provide those skilled in the art with anenabling description for implementing the embodiments. It beingunderstood that various changes may be made in the function andarrangement of elements without departing from the spirit and scope ofthe appended claims.

An embodiment of a manufacturing system with a test system 100 is shownin FIG. 1. The manufacturing system with a test system 100 can include amanufacturing line 102. The manufacturing line 102 can be a conveyorbelt, rollers, or other system of moving or transporting articles ofmanufacture through the manufacturing process. In the construction of anintegrated circuit board, a thermally-enhanced IC 106 is mounted upon asubstrate, such as circuit board 104, to create the integrated circuitboard 107. This integrated circuit board 107 can be transported alongthe manufacturing line 102, until the integrated circuit board 107enters a test area 108. In the test area 108, a power harness 110 can beconnected to the IC 106 to operate the IC 106. The operation of the IC106 can generate heat which may be imaged or viewed by a thermal imagingcamera or device 112. In other embodiments, power harness 110 isreplaced by a heat generating device which may be placed on or near theIC 106 to create a heat source that can be used to image the connectionbetween the IC 106 and the circuit board 104. The thermal imaging camera112 can be any thermal imaging camera 112 that can detect thermalgradients or changes in the area of the IC 106 mounting on the circuitboard 104. An example of the thermal imaging camera 112 can include DM2900 Thermocam camera sold by Inframetrics, Inc. of North Billerica,Mass. If the IC 106 on the circuit board 104 passes one or more tests,the integrated circuit board 107 may then be sent on through themanufacturing process. However, if the mounting of the IC 106 does notpass the thermal imaging test, the failed circuit board 107 may beremoved from the manufacturing process and be reworked to properly mountthe IC 106. In other embodiments, the failed circuit board may bedisposed.

Embodiments of integrated circuit board 107 shown before and after themounting of a thermally-enhanced IC 106 is shown in FIGS. 2A and 2C. Thecircuit board 104 before mounting, shown in FIG. 2A, can include asubstrate 202, which may be a printed circuit board or some othermounting hardware, one or more electrical connection pads 206 formounting an IC 106, one or more harness connection points 208, amounting pad 204, and one or more other electrical components (notshown). The substrate 202 can include a mounting pad 204 which generallyis constructed of a thermally-conductive material such as metal. Themetal or thermally-conductive pad can dissipate heat from the heat sinkof the thermally-enhanced IC 106 through the substrate 202. Thesubstrate 202 can include one or more electrical connection pads 206which may be used to mount the pins, balls, or other leads which sendelectrical systems into and out of the IC 106 from the substrate 202.

The substrate 202 may also include one or more harness connection points208A through C that connect to one or more of the electrical connectionpads 206. These harness connection points 208 allow for the powerharness 110 to be coupled or placed in electrical connection with the IC106 once the IC 106 is mounted. In other embodiments, the substrate 202does not include harness mounting points 208, as the power harness 110can connect directly to the pins or leads of the IC 106.

An embodiment of a thermally-enhanced integrated circuit 106 is shown inFIG. 2B. An IC 106 can be a die that includes the integrated circuitcomponents enclosed in a package 210 that mounts to a circuit board 104.FIG. 2B provides a prospective of the underside of the IC 106. It shouldbe noted that a thermal-enhanced quad flack pack is shown in FIG. 2B.However, other types of thermally-enhanced ICs 106 may be used. Forexample, the manufacturing system with a test system 100 is operable totest dual inline package ICs, ball grade array ICs, pin grid array ICs,small outline package ICs, or other types of IC packages. Here, the heatsink 212 is shown on the bottom of the IC 106. The heat sink 212 may bein thermal conductivity with the die within the IC package 210 of the IC106. The package 210 is the enclosure that houses the die that is placedwithin the IC package 210 of the IC 106. The IC package 210 may includeone or more pins or leads 214 extending from the IC package 210. Thepins 214 make electrical connections between the substrate 202104 andthe die within the IC package 210.

An embodiment of the circuit board 104 with the IC 106 mounted upon itis shown in FIGS. 2C and 2D, although from different perspectives. Here,the IC 106 is shown as mounted to the substrate 202, where the heat sink212 is in thermal conductivity or connection with the mounting pad 204.This drawing can show the final manufacturing stage or may be anintermediate stage where other electrical components may be placed onthe electrical substrate 202. Regardless, the integrated circuit board107 can be tested with the IC 106 mounted to determine if the thermalconnection between the heat sink 212 and the mounted pad 204 is properand functional.

Embodiments of the views from the thermal imaging camera 112 of thetested integrated circuit board 107 are shown in FIGS. 3A through 3C. InFIG. 3A, a properly mounted thermally-enhanced QFP is shown where thered area or lighter area between the heat sink 212 and the mounting pad204 is shown. Here, the thermal conductivity is good between the heatsink 212 and the mounting pad 204 and, thus, the IC 106 is mountedproperly upon the circuit board 104.

Several errors can occur in mounting the thermally-enhanced IC 106 tosubstrate 202. Those errors can include voids in the soldering, caninclude solder which does not fully bridge the gap between the heat sink212 and the mounting pad 204, bad wetting of the heat sink 212 and/ormounting pad 204, or other types of errors. Thermal images of some ofthese errors are shown in FIGS. 3B and 3C. In FIG. 3B, the darker orblue areas 302 show that there are voids in the soldering between theheat sink 212 and the mounting pad 204. Thus, there is not good thermalconduction between the heat sink 212 and the mounting pad 204. Theintegrated circuit board 107 shown in FIG. 3B would need to be reworkedto remount the IC 106 on the substrate 202. FIG. 3C shows a darker area304 shown in the thermal image view that shows, while the solder hasbeen placed along the entire surface between the heat sink 212 and themounting pad 204, there is an area where the solder does not fullybridge the gap between the heat sink 212 and the mounting pad 204. Assuch, heat may be dissipated through this area, but the connection isnot providing as good a thermal conduction path as can be provided ifthe IC 106 is properly mounted on the circuit board 104.

An embodiment of a test system 402 is shown in FIG. 4. The test system402 may include one or more software modules that are executed on acomputer system as described in conjunction with FIGS. 7 and 8. In otherembodiments, the modules may be incorporated in a hardware system, suchas a Field Programmable Gate Array or an Application Specific IntegratedCircuit. The test system 402 can include a test control module 404, apower harness module 408, a thermal camera module 410, a manufacturingline module 416, and a user interface 412.

The test control module 404 can receive one or more inputs from the testenvironment 406 that shall dictate how tests are conducted. The testenvironment 406 may be the same or similar to the test area 108 shown inFIG. 1. An input can be anything that can initiate, modify, or terminatetesting of an integrated circuit board 107. For example, the testenvironment input could include an indication that a new integratedcircuit board 107 has entered the test area 108 and needs to begintesting. Other environmental inputs can include the pausing of themanufacturing line 102 or changes in the speed or rate at whichintegrated circuit boards 107 are made. Further, the test control module404 is also responsible for controlling the one or more other modules inthe test system 402. As such, the test control module 404 can sendcommand signals to the other modules to have the other modules executefunctions or may receive inputs from the other modules that can causethe test control module 404 to conduct actions.

The power harness module 408 is a component which controls the powerharness 110. As such, the power harness module 408 can maneuver or movethe power harness 110 such that the power harness 110 is electricallyconnected to the IC 106. Further, the power harness module 408 cansignal or cause the power harness 110 to supply power to the IC 106,thus, creating heat from the execution of the IC 106. The power harnessmodule 408 can also conduct one or more communications sequences withthe IC 106 to cause the IC 106 to execute one or more operations thatcan generate heat.

The manufacturing line module 416 communicates to the manufacturing line102. Thus, the manufacturing line module 416 can cause manufacturingline 102 to stop, speed up, pause, or other execute other functions thatare required in order to test the circuit board 104. The thermal cameramodule 410 is operable to control thermal imaging camera 112. Thus, thethermal camera module 410 can cause the thermal imaging camera 112 tomove, focus, or generate a picture which can be sent from the thermalcamera module 410 to the user interface 412 to be displayed on a displaydevice 414 (or “display” 414). The thermal camera module 410 may alsoadjust the thermal imaging camera 112 to produce a better picture basedon one or more user inputs received through a user interface 412 thatare received by the test control module 404. The test control module 404may also interact with the user through the user interface 412. Thus,test system 402 configuration changes or tests may be received in thetest control module 404 through the display 414 or user interface 412.

An embodiment of a process to test an integrated circuit board 107 isshown in FIG. 5. Generally, the method 500 begins with a start operation502 and terminates with an end operation 522. While a general order forthe steps of the method 500 are shown in FIG. 5, the method 500 caninclude more or fewer steps or arrange the order of the stepsdifferently than those shown in FIG. 5. The method 500 can be executedas a set of computer-executable instructions executed by a computersystem and encoded or stored on a computer readable medium. Hereinafter,the method 500 shall be explained with reference to the systems,components, modules, software, data structures, etc. described inconjunction with FIGS. 1-4.

The test area 108 receives an integrated circuit board 107 having athermally-enhanced IC 106 placed on the circuit board 104, in step 504.The manufacturing line 102 can move the integrated circuit board 107into the test area 108. Once in the test area 108, the test system 402can recognize that the integrated circuit board 107 has entered the testarea 108. The test system 402 may determine what type of integratedcircuit board 107 has entered the test area 108. For example, the testsystem 402 can receive an input from the test environment 406 to thetest control module 404. The input can be a part number scan or someother identification, which may be received by any known method, such asRFID, visual or scanning, or other methods. In embodiments, themanufacturing line 102 may be controlled by the manufacturing linemodule 416, such that as integrated circuit boards 107 enter the testarea 108, the manufacturing line 102 can be stopped, slowed, or proceedas normal depending upon signals sent from the manufacturing line module416.

Once the test control module 404 has determined that an integratedcircuit board 107 has entered the test area 108, the test control module404 can determine a test scenario, in step 506. A test scenario is anytest or set of tests that may be performed on the integrated circuitboard 107 while in the test area 108. One of those tests can be thethermal imaging of the IC 106 to determine if the soldering or physicalfixation of the thermally-enhanced IC 106 to the circuit board 104passes a set of criteria or tests. If the test control module 404determines that a thermal image test will be performed, the test controlmodule 404 can execute the tests in an area for imaging the IC 106 withthe thermal imaging camera 112.

The test control module 404 may first send a signal to the power harnessmodule 408 or some other module to connect a heat source or powerharness 110 to the IC 106, in step 508. Thus, the power harness module408 may maneuver the power harness 110 into physical connection with theIC 106. The power harness module 408 may then instruct the power harness110 to send an electric current or power to the IC 106 or to send one ormore other signals to cause the IC 106 to generate heat. In otherembodiments, the power harness module 408 may control another heatsource besides the power harness 110, which may be connected to the heatsink 212 or the pad 204 on the circuit board 104. The test controlmodule 404 may wait a period of time based on the test scenario and thenmay instruct the thermal camera module 410 to execute a test or scanwith thermal imaging camera 112.

The thermal camera module 410 can send a signal to the thermal imagingcamera 112 to image the IC 106 after the heat has substantiallyincreased to conduct a scan, in step 510. The thermal imaging camera 112can take one or more pictures or may take a video of the IC 106 and sendthe information back to the thermal camera module 410. The thermalcamera module 410 may determine if the thermal images sent from thethermal imaging camera 112 are sufficient, in step 512. For example, thethermal camera module 410 may determine whether the images meet or passone or more tests that detect whether the thermal imaging camera 112operated correctly. For example, the thermal camera module 410 maydetermine if there are a predetermined number of pixels that were withina color range that would indicate heat has been detected. If asufficient number of pixels are shown, the thermal camera module 410,may determine if there are voids within the picture, (e.g. pixels thatare not showing color), or some other test that can determine if theimage has been taken correctly by the thermal imaging camera 112. If theimage is not sufficient, step 512 proceeds “NO” to step 514, where thethermal camera module 410 may adjust the thermal imaging camera 112.Adjusting the thermal imaging camera 112 may include changing the focus,changing the position, or changing of one or more internal settings ofthe thermal imaging camera 112 to create a better image. If the thermalimaging camera 112 cannot be adjusted, the thermal camera module 410 maysend an error message to the test control module 404, which may then bethe error message, to be presented to a display 414 through the userinterface 412. Once presented, the error message can instruct testpersonnel to inspect the thermal imaging camera 112 to ensure it isoperating correctly. If the image is sufficient, step 512 proceeds “YES”to step 516.

In step 516, the test control module 404, or a human tester, maydetermine if the IC 106 passes the thermal image test. The thermalimage, from the thermal imaging camera 112, may be passed from thethermal camera module 410 through a user interface 412 to a display 414.Once on a display 414, a human tester may view the thermal image anddetermine if the connection of the thermally-enhanced IC 106 to thecircuit board 104 has one or more possible errors as described in FIG.3A or 3C, or one or more errors that may be determined from the thermalimage.

In other embodiments, the test control module 404 or thermal cameramodule 410 can conduct an automatic test of the image. For example, thethermal camera module 410 or test control module 404 can scan for pixelswhich are not within a certain color range of other surrounding pixels.The scan may be isolated to those pixels that should be within the heatdissipation area of the heat sink 212 and the mounting pad 204. Forexample, if a color is more blue or green, rather than orange, yellow,or red, then there may be some problem with the soldering of the IC 106to the circuit board 104. If the integrated circuit board 107 passes thetest, step 516 proceeds “YES” to continue manufacturing, in step 520. Inthat case, the integrated circuit board 107 may proceed down themanufacturing line 102 or may begin the process of being shipped to acustomer. If the integrated circuit board 107 does not pass the test,step 516 proceeds “NO” to step 518. In step 518, the integrated circuitboard 107 may be sent to be reworked and the IC 106 re-soldered onto thecircuit board 104.

An embodiment of a method 600 for testing an integrated circuit board107 with a thermal imaging camera 112 is shown in FIG. 6. Generally, themethod 600 begins with a start operation 602 and terminates with an endoperation 622. While a general order for the steps of the method 600 areshown in FIG. 6, the method 600 can include more or fewer steps orarrange the order of the steps differently than those shown in FIG. 6.The method 600 can be executed as a set of computer-executableinstructions executed by a computer system and encoded or stored on acomputer readable medium. Hereinafter, the method 600 shall be explainedwith reference to the systems, components, modules, software, datastructures, etc. described in conjunction with FIGS. 1-4.

A test system 402 receives a thermal image, in step 604. The thermalimage may be sent from a thermal imaging camera 112 to a thermal cameramodule 410 in the test system 402. The thermal image can be processedeither by the thermal camera module 410, or by a test control module404. Thus, if the test control module 404 is to process the thermalimage, the thermal camera module 410 sends the thermal image to the testcontrol module 404.

Testing for whether the thermally-enhanced IC 106 is properly mounted tothe circuit board 104 may be done automatically. As such, the thermalcamera module 410 or test control module 404 can scan the thermal imageto determine if there are signs of cold or cool areas, in step 606. Acold or cool area may be determined by the thermal module 410 or thetest control module 404 by the color value for pixel within the thermalimage. For example, there may be a pre-determined threshold set by atester where if the pixel value for color is below that value, then thepixels determine to be cold or cool. In other embodiments, the testermay set a range of pixel values which designate a cold area. Generally,the pixel values will be four colors in the yellow, green, blue, purple,or other dark color values. If there are cold areas within the thermalimage, step 606 may proceed “YES” to step 608. If there are no signs ora limited amount of signs of cold areas, step 606 may proceed “NO” tothe end operation 622. Thus, the thermal camera module 410 or testcontrol module 404 can determine if there are enough cold areas withinthe thermal image to warrant further investigation.

The test control module 404 or the thermal cameral module 410 may thenautomatically determine the number of cold areas, in step 608. A coldarea may be determined by a pre-determined number of pixels that arewithin close proximity of each other. For example, to be designated as acold area, two or more pixels may need to be in close proximity. Inother embodiments, the number of pixels can be set by the tester to beany number of pixels, for example, two or more pixels may designate acold area. The pixels may be in close proximity if they were apre-determined number of pixels from each other. For example, if the twopixels are of each other, then those two pixels are deemed to be withinclose proximity. The number of pixels, required to be designated withinclose proximity, may be set by the tester and can be any number ofpixels. After determining the cold areas, the test control module 404 orthe thermal camera module 410 can count the number of designated coldareas.

The thermal camera module 410 or test control module 404 may thendetermine the size of the cold areas counted in step 608, in step 610.The size of the cold areas may be determined by the number of pixelshaving a dark color value within the cold area. Thus, the thermal cameramodule 410 or test control module 404 can count the number of pixels ineach of the different cold areas. In other embodiments, another typemethod for determining the size of the cold area may be used. Forexample, the test control module 404 or thermal camera module 410 maydetermine a relative area for the cold areas. This area may be deducedby a physical measurement of the cold area and comparing that to therelative scale of the thermal image. For example, if the thermal imagerepresents a ten times view of the thermally-enhanced IC 106, then thephysical measurement of the cold area can be multiplied by ten todetermine the actual physical area of the cold area in the thermalimage.

The thermal camera module 410 or test control module 404 may thendetermine intensity for each of the cold areas, in step 612. Theintensity of a cold area can be determined by the pixel values of thedarker areas within the cold areas. For example, an average value forthe pixels within the cold area may be determined. Thus, each pixelvalue may be summed and divided by the total number of pixels within thecold area to determine the average. This average pixel value can becompared against the threshold or can be compared to other cold areaswithin the thermal image. Regardless, the average intensity of thepixels within the cold area can give a relative idea of the intensity ofthe cold area.

To determine whether the thermally-enhanced IC 106 is properly mountedto the circuit board 104, the thermal camera module 410 or test controlmodule 404 can compare the different measurements provided or generatedfrom step 608, 610 and 612 to one or more criteria, in step 614. Thecriteria may be established by a tester and entered into the testcontrol module 404 for the test scenario. Each different measurementfrom step 608, 610, and 612 may be measured or compared against separatecriteria. For example, the number of cold areas can be compared to athreshold, for example, three cold areas, to determine if the number ofcold areas is over a threshold for whether the thermally-enhanced IC 106is properly mounted to the circuit board 104. In another example, thesize of the cold areas can be compared against the threshold, forexample, five pixels within the cold area, to determine if thethermally-enhanced IC 106 is mounted properly. Further, the intensity ofthe cold area can be compared against the threshold, such as a maximumintensity of a cold area compared to the average pixel value for each ofthe cold areas or a maximum intensity threshold for all cold areascompared to an average of all cold area pixels in all of the cold areas.If any one of the criteria or measurements crosses the threshold, thenthe thermally-enhanced IC 106 to determine not to be properly mounted.In other embodiments, either all three tests fail or one or more testsmust fail, as set by a tester.

The thermal camera module 410 or test control module 404 may bedetermined by the comparison to the criteria whether the integratedthermally-enhanced IC 106 is mounted properly to the circuit board 104and the integrated circuit board 107 passes the test, in step 616. Assuch, the thermal camera module 410 or test control module 404 mayevaluate each of the comparisons to the criteria and determine based onpre-determined requirements from the tester whether the integratedcircuit board 107 passes the thermal imaging test. If the integratedcircuit board 107 passes the thermal imagining test in step 616 proceeds“YES” to step 620. In contrast, if the integrated circuit board 107 doesnot pass the thermal imaging test in step 616 proceeds “NO” to step 618.

In step 618, the integrated circuit board 107 is sent to a reworkstation to be reworked. In embodiments, the thermally-enhanced IC 106may be removed from the circuit board 104 and re-soldered and testedagain. In other embodiments, the circuit board 104 may be scrapped.

In step 620, the integrated circuit board 107 can continuemanufacturing. Continue manufacturing may be the placement of one ormore additional parts, thermal coating, or other steps used in themanufacturing process. In embodiments, the integrated circuit board 107reaches the end of manufacturing and packaged and shipped to a customer.

FIG. 7 illustrates a block diagram of a computing environment 700. Thesystem 700 includes one or more computers 705, 710, and 715. Thecomputers 705, 710, and 715 may be general purpose personal computers(including, merely by way of example, personal computers and/or laptopcomputers running various versions of Microsoft Corp.'s Windows® and/orApple Corp.'s Macintosh® operating systems) and/or workstation computersrunning any of a variety of commercially-available UNIX® or UNIX-likeoperating systems. These computers 705, 710, 715 may also have any of avariety of applications, including for example, database client and/orserver applications, and web browser applications. Alternatively, thecomputers 705, 710, and 715 may be any other electronic device, such asa thin-client computer, mobile telephone, mobile device,Internet-enabled mobile telephone, and/or personal digital assistant,capable of communicating via a network (e.g., the network 720 describedbelow) and/or displaying and navigating web pages or other types ofelectronic data. Although the exemplary system 700 is shown with threecomputers, any number of computers may be supported.

System 700 further includes a network 720. The network 720 may can beany type of network familiar to those skilled in the art that cansupport data communications using any of a variety ofcommercially-available protocols, including without limitation TCP/IP,SNA, IPX, AppleTalk, and the like. Me'rely by way of example, thenetwork 720 maybe a local area network (“LAN”), such as an Ethernetnetwork, a Token-Ring network and/or the like; a wide-area network; avirtual network, including without limitation a virtual private network(“VPN”); the Internet; an intranet; an extranet; a public switchedtelephone network (“PSTN”); an infra-red network; a wireless network(e.g., a network operating under any of the IEEE 802.11 suite ofprotocols, the Bluetooth® protocol known in the art, and/or any otherwireless protocol); and/or any combination of these and/or othernetworks.

The system 700 may also include one or more server computers 725 and730. The server computers 725 and/or 730 can represent the test system402. One server may be a web server 725, which may be used to processrequests for web pages or other electronic documents from user computers705, 710, and 720. The web server can be running an operating systemincluding any of those discussed above, as well as anycommercially-available server operating systems. The web server 725 canalso run a variety of server applications, including HTTP servers, FTPservers, CGI servers, database servers, Java servers, and the like. Insome instances, the web server 725 may publish operations availableoperations as one or more web services.

The system 700 may also include one or more file and or/applicationservers 730, which can, in addition to an operating system, include oneor more applications accessible by a client running on one or more ofthe user computers 705, 710, 715. The server(s) 730 may be one or moregeneral purpose computers capable of executing programs or scripts inresponse to the user computers 705, 710 and 715. As one example, theserver may execute one or more web applications. The web application maybe implemented as one or more scripts or programs written in anyprogramming language, such as Java™, C, C# or C++, and/or any scriptinglanguage, such as Perl, Python, or TCL, as well as combinations of anyprogramming/scripting languages. The application server(s) 730 may alsoinclude database servers, including without limitation thosecommercially available from Oracle, Microsoft, Sybase™, IBM™ and thelike, which can process requests from database clients running on a usercomputer 705.

The web pages created by the web application server 730 may be forwardedto a user computer 705 via a web server 725. Similarly, the web server725 may be able to receive web page requests, web services invocations,and/or input data from a user computer 705 and can forward the web pagerequests and/or input data to the web application server 730. In furtherembodiments, the server 730 may function as a file server. Although forease of description, FIG. 7 illustrates a separate web server 725 andfile/application server 730, those skilled in the art will recognizethat the functions described with respect to servers 725, 730 may beperformed by a single server and/or a plurality of specialized servers,depending on implementation-specific needs and parameters.

The system 700 may also include a database 735. The database 735 mayreside in a variety of locations. By way of example, database 735 mayreside on a storage medium local to (and/or resident in) one or more ofthe computers 705, 710, 715, 725, 730. Alternatively, it may be remotefrom any or all of the computers 705, 710, 715, 725, 730, and incommunication (e.g., via the network 720) with one or more of these. Ina particular set of embodiments, the database 735 may reside in astorage-area network (“SAN”) familiar to those skilled in the art.Similarly, any necessary files for performing the functions attributedto the computers 705, 710, 715, 725, 730 may be stored locally on therespective computer and/or remotely, as appropriate. In one set ofembodiments, the database 735 may be a relational database, such asOracle 10i®, that is adapted to store, update, and retrieve data inresponse to SQL-formatted commands.

FIG. 8 illustrates one embodiment of a computer system 800 upon whichthe test system 402 may be deployed or executed. The computer system 800is shown comprising hardware elements that may be electrically coupledvia a bus 855. The hardware elements may include one or more centralprocessing units (CPUs) 805; one or more input devices 810 (e.g., amouse, a keyboard, etc.); and one or more output devices 815 (e.g., adisplay device, a printer, etc.). The computer system 800 may alsoinclude one or more storage devices 820. By way of example, storagedevice(s) 820 may be disk drives, optical storage devices, solid-statestorage devices, such as a random access memory (“RAM”) and/or aread-only memory (“ROM”), which can be programmable, flash-updateable,and/or the like.

The computer system 800 may additionally include a computer-readablestorage media reader 825; a communications system 830 (e.g., a modern, anetwork card (wireless or wired), an infra-red communication device,etc.); and working memory 840, which may include RAM and ROM devices asdescribed above. In some embodiments, the computer system 800 may alsoinclude a processing acceleration unit 835, which can include a DSP, aspecial-purpose processor and/or the like

The computer-readable storage media reader 825 can further be connectedto a computer-readable storage medium, together (and, optionally, incombination with storage device(s) 820) comprehensively representingremote, local, fixed, and/or removable storage devices plus storagemedia for temporarily and/or more permanently containingcomputer-readable information. The communications system 830 may permitdata to be exchanged with the network 820 and/or any other computerdescribed above with respect to the system 800. Moreover, as disclosedherein, the term “storage medium” may represent one or more devices forstoring data, including read only memory (ROM), random access memory(RAM), magnetic RAM, core memory, magnetic disk storage mediums, opticalstorage mediums, flash memory devices, and/or other machine readablemediums for storing information.

The computer system 800 may also comprise software elements, shown asbeing currently located within a working memory 840, including anoperating system 845 and/or other code 850, such as program codeimplementing the components and software described herein. It should beappreciated that alternate embodiments of a computer system 800 may havenumerous variations from that described above. For example, customizedhardware might also be used and/or particular elements might beimplemented in hardware, software (including portable software, such asapplets), or both. Further, connection to other computing devices suchas network input/output devices may be employed.

In the foregoing description, for the purposes of illustration, methodswere described in a particular order. It should be appreciated that inalternate embodiments, the methods may be performed in a different orderthan that described. It should also be appreciated that the methodsdescribed above may be performed by hardware components or may beembodied in sequences of machine-executable instructions, which may beused to cause a machine, such as a general-purpose or special-purposeprocessor or logic circuits programmed with the instructions to performthe methods. These machine-executable instructions may be stored or oneor more machine readable mediums, such as CD-ROMs or other type ofoptical disks, floppy diskettes, ROMs, RAMs, EPROMs, EEPROMs, magneticor optical cards, flash memory, or other types of machine-readablemediums suitable for storing electronic instructions. Alternatively, themethods may be performed by a combination of hardware and software.

Specific details were given in the description to provide a thoroughunderstanding of the embodiments. However, it will be understood by oneof ordinary skill in the art that the embodiments may be practicedwithout these specific details. For example, circuits may be shown inblock diagrams in order not to obscure the embodiments in unnecessarydetail. In other instances, well-known circuits, processes, algorithms,structures, and techniques may be shown without unnecessary detail inorder to avoid obscuring the embodiments.

Also, it is noted that the embodiments were described as a process whichis depicted as a flowchart, a flow diagram, a data flow diagram, astructure diagram, or a block diagram. Although a flowchart may describethe operations as a sequential process, many of the operations can beperformed in parallel or concurrently. In addition, the order of theoperations may be re-arranged. A process is terminated when itsoperations are completed, but could have additional steps not includedin the figure. A process may correspond to a method, a function, aprocedure, a subroutine, a subprogram, etc. When a process correspondsto a function, its termination corresponds to a return of the functionto the calling function or the main function.

Furthermore, embodiments may be implemented by hardware, software,firmware, middleware, microcode, hardware description languages, or anycombination thereof. When implemented in software, firmware, middlewareor microcode, the program code or code segments to perform the necessarytasks may be stored in a machine readable medium such as storage medium.A processor(s) may perform the necessary tasks. A code segment mayrepresent a procedure, a function, a subprogram, a program, a routine, asubroutine, a module, a software package, a class, or any combination ofinstructions, data structures, or program statements. A code segment maybe coupled to another code segment or a hardware circuit by passingand/or receiving information, data, arguments, parameters, or memorycontents. Information, arguments, parameters, data, etc. may be passed,forwarded, or transmitted via any suitable means including memorysharing, message passing, token passing, network transmission, etc.

While illustrative embodiments have been described in detail herein, itis to be understood that the inventive concepts may be otherwisevariously embodied and employed, and that the appended claims areintended to be construed to include such variations, except as limitedby the prior art.

1. A method for testing an integrated circuit board, the methodcomprising: receiving the integrated circuit board, wherein integratedcircuit board includes a thermally-enhanced integrated circuit mountedon a circuit board; connecting the thermally-enhanced integrated circuitto one of a group comprising a power harness and a heat source; imagingthe thermally-enhanced integrated circuit with a thermal imaging camerato produce a thermal image of the thermally-enhanced integrated circuitwhile the thermally-enhanced integrated circuit is operating; anddetermining, from the thermal image, if the thermally-enhancedintegrated circuit is properly mounted to the circuit board.
 2. Themethod as defined in claim 1, wherein the thermally-enhanced integratedcircuit includes a heat sink that is mounted on a mounting pad on thecircuit board.
 3. The method as defined in claim 2, wherein the thermalimage images the mounting of the heat sink that to the mounting pad. 4.The method as defined in claim 1, further comprising determining a testscenario, wherein the test scenario includes two or more tests, whereinone of the two or more tests is the thermally-enhanced integratedcircuit with a thermal imaging camera.
 5. The method as defined in claim1, further comprising: determining if the thermal image is sufficient;if the thermal image is sufficient, determining from the thermal imageif the thermally-enhanced integrated circuit is properly mounted to thecircuit board; and if the thermal image is not sufficient, adjusting thethermal imaging camera.
 6. The method as defined in claim 5, whereindetermining if the thermal image is sufficient comprises conducting oneor more tests on the thermal image, wherein a test on the thermal imageincludes one of the group comprising determining if there are apredetermined number of image pixels within a predetermined color rangeand determining if there are one or more voids within the thermal imagewhere no color is shown.
 7. The method as defined in claim 1, furthercomprising: if the thermally-enhanced integrated circuit is properlymounted to the circuit board, continuing manufacturing of the integratedcircuit board; and if the thermally-enhanced integrated circuit is notproperly mounted to the circuit board, reworking the integrated circuitboard.
 8. The method as defined in claim 1, wherein a test systemautomatically determines if the thermally-enhanced integrated circuit isproperly mounted to the circuit board, wherein automatically determiningif the thermally-enhanced integrated circuit is properly mounted to thecircuit board comprises: determining if there are one or moreindications of cold areas in the thermal image; if there are not one ormore indications of cold areas in the thermal image, determining thatthe thermally-enhanced integrated circuit is properly mounted to thecircuit board; if there are one or more indications of cold areas in thethermal image, determining a number of cold areas; determining a sizefor each of the determined cold areas; determining an intensity for eachof the determined cold areas; comparing at least one of the number ofcold areas, the size for each of the determined cold areas, and theintensity for each of the determined cold areas with one or morecriteria; and from the comparison, determining if the thermally-enhancedintegrated circuit is properly mounted to the circuit board.
 9. A testsystem comprising: a manufacturing line, wherein a thermally-enhancedintegrated circuit is mounted to a circuit board while on themanufacturing line to create an integrated circuit board; a test area,wherein the manufacturing line moves the integrated circuit board intothe test area, the test area comprising: a power harness electricallyconnected to the thermally-enhanced integrated circuit after theintegrated circuit board enters the test area, the power harnessoperable to provide power and execute the thermally-enhanced integratedcircuit while on the circuit board; a thermal imaging camera disposed toproduce a thermal image of the thermally-enhanced integrated circuitmounted on the circuit board, wherein proper mounting of thethermally-enhanced integrated circuit is determined from the thermalimage.
 10. The test system as defined in claim 9, further comprising atest system, the test system comprising: a memory; a processor incommunication with the memory, the processor operable to execute: apower harness module operable to control the power harness; amanufacturing line module operable to control the manufacturing line; athermal camera module operable to control the thermal imaging camera;and a test control module operable to control the power harness module,the manufacturing line module, and the thermal camera module.
 11. Thetest system as defined in claim 10, wherein the test control moduleoperable to: receive a test environment input that the integratedcircuit board has entered the test area; command the power harnessmodule to connect the power harness to the thermally-enhanced integratedcircuit; wait until heat dissipation of the thermally-enhancedintegrated circuit reaches a steady state; command the thermal cameramodule to operate the thermal imaging camera to image thethermally-enhanced integrated circuit to produce the thermal image; anddetermine, from the thermal image, if the thermally-enhanced integratedcircuit is properly mounted to the circuit board.
 12. The test system asdefined in claim 10, wherein the test control module operable todetermine a test scenario for the integrated circuit board, wherein thetest scenario includes two or more tests.
 13. The test system as definedin claim 10, wherein the test control module operable to: determine ifthe thermal image has a predetermined number of image pixels within apredetermined color range; determine if there are one or more voidswithin the thermal image where no color is shown; if the thermal imagedoes have the predetermined number of image pixels within thepredetermined color range and if there are no voids within the thermalimage where no color is shown, determine from the thermal image if thethermally-enhanced integrated circuit is properly mounted to the circuitboard; and if the thermal image does not have the predetermined numberof image pixels within the predetermined color range and if there areone or more voids within the thermal image where no color is shown,command the thermal cameral module to adjust the thermal imaging camera.14. The test system as defined in claim 10, wherein the test controlmodule operable to: if the thermally-enhanced integrated circuit isproperly mounted to the circuit board, command the manufacturing linemodule to have the manufacturing line continue manufacturing theintegrated circuit board; and if the thermally-enhanced integratedcircuit is not properly mounted to the circuit board, command themanufacturing line module to have the manufacturing line rework theintegrated circuit board.
 15. The test system as defined in claim 10,wherein the test control module is operable to automatically determineif the thermally-enhanced integrated circuit is properly mounted to thecircuit board, wherein to automatically determine if thethermally-enhanced integrated circuit is properly mounted to the circuitboard, the test control module operable to: determine if there are oneor more indications of cold areas in the thermal image; if there is notone or more indications of cold areas in the thermal image, determinethat the thermally-enhanced integrated circuit is properly mounted tothe circuit board; if there are one or more indications of cold areas inthe thermal image, determine a number of cold areas; determine a sizefor each of the determined cold areas; determine an intensity for eachof the determined cold areas; compare at least one of the number of coldareas, the size for each of the determined cold areas, and the intensityfor each of the determined cold areas with one or more criteria; andfrom the comparison, determine if the thermally-enhanced integratedcircuit is properly mounted to the circuit board.
 16. An integratedcircuit board created by a manufacturing process, the manufacturingprocess comprising: receiving a circuit board; receiving athermally-enhanced integrated circuit; placing the thermally-enhancedintegrated circuit on the circuit board; soldering thethermally-enhanced integrated circuit to the circuit board to create theintegrated circuit board; receiving the integrated circuit board in atest area; connecting the thermally-enhanced integrated circuit to apower harness; imaging the thermally-enhanced integrated circuit with athermal imaging camera to produce a thermal image of thethermally-enhanced integrated circuit while the thermally-enhancedintegrated circuit is operating; and determining, from the thermalimage, if the thermally-enhanced integrated circuit is properly mountedto the circuit board.
 17. The integrated circuit board as defined inclaim 16, wherein the manufacturing process further comprises: if thethermally-enhanced integrated circuit is properly mounted to the circuitboard, continuing manufacturing of the integrated circuit board; and ifthe thermally-enhanced integrated circuit is not properly mounted to thecircuit board, reworking the integrated circuit board.
 18. Theintegrated circuit board as defined in claim 16, wherein the propermounting of the thermally-enhanced integrated circuit to the circuitboard is automatically determined, wherein automatically determining ifthe thermally-enhanced integrated circuit is properly mounted to thecircuit board comprises: determining if there are one or moreindications of cold areas in the thermal image; if there are not one ormore indications of cold areas in the thermal image, determining thatthe thermally-enhanced integrated circuit is properly mounted to thecircuit board; if there are one or more indications of cold areas in thethermal image, determining a number of cold areas; determining a sizefor each of the determined cold areas; determining an intensity for eachof the determined cold areas; comparing at least one of the number ofcold areas, the size for each of the determined cold areas, and theintensity for each of the determined cold areas with one or morecriteria; and from the comparison, determining if the thermally-enhancedintegrated circuit is properly mounted to the circuit board.
 19. Theintegrated circuit board as defined in claim 16, wherein thethermally-enhanced integrated circuit is one of a group consisting of athermally-enhanced quad flat pack, a thermally-enhanced ball grid array,and a thermally-enhanced small outline package.
 20. The integratedcircuit board as defined in claim 16, wherein the thermally-enhancedintegrated circuit is not properly mounted to the circuit board if thethermal image shows one error of a group consisting of no solder beneaththe thermally-enhanced integrated circuit, poor wetting between solderand a heat sink on the thermally-enhanced integrated circuit, and apartial lack of solder bridging a gap between a heat sink on thethermally-enhanced integrated circuit and a mounting pad on the circuitboard.